Scale of the universe

jez101

Bookies drive nice cars because of people like me
Contributor
Do you think there is a little white fence with "The Edge of Space" written on it forming a nice little boundary so that we can put a number like 93 billion to it? Do we really think that space just stops? What is there a mile further away, or a billion miles, or 100 billion miles? Personally, I can't see how there could be a limit... Why do people struggle with the idea of infinity?:thinking:

(I do have some background here - both my parents were astronomers and I grew up with black holes being discussed over dinner. No formal education, but much philosohpical stimulation...)
 

Mryzyz

Rookie
Do you think there is a little white fence with "The Edge of Space" written on it forming a nice little boundary so that we can put a number like 93 billion to it? Do we really think that space just stops? What is there a mile further away, or a billion miles, or 100 billion miles? Personally, I can't see how there could be a limit... Why do people struggle with the idea of infinity?:thinking:

(I do have some background here - both my parents were astronomers and I grew up with black holes being discussed over dinner. No formal education, but much philosohpical stimulation...)

If go far enough in a straight line in one direction, you will eventually end up back where you started. Provided you don't crash into anything.
 

Jen

Here be dragons.
Contributor
If go far enough in a straight line in one direction, you will eventually end up back where you started. Provided you don't crash into anything.
That's only true if you are going 'round' something surely? A straight line suggests that there is no end to it and, so, can't possibly revert to the start point. Or were you speaking metaphorically?
 

jez101

Bookies drive nice cars because of people like me
Contributor
I watched "Wonders of the Universe" on BBC1 last night. If this thread is interesting to you, all I can say is try and catch that on iPlayer or whatever. It was all about time and looked at the really big big picture!
 
I used to have problems with infinite space, I.e. How can I fall forever in space?

However the big bang, starting from one point and then expanding space into the nothingness around it works well because as I fall new space is been created under me

(as long as there is no contraction back to the single point)
 

tooncheese

Hans Heyer
Contributor
Do you think there is a little white fence with "The Edge of Space" written on it forming a nice little boundary so that we can put a number like 93 billion to it? Do we really think that space just stops? What is there a mile further away, or a billion miles, or 100 billion miles? Personally, I can't see how there could be a limit... Why do people struggle with the idea of infinity?:thinking:

(I do have some background here - both my parents were astronomers and I grew up with black holes being discussed over dinner. No formal education, but much philosohpical stimulation...)

We are at the edge and the centre of the universe, we are where the big bang happened*. Infinity confuses me a fair bit as my brain demands a set answer to everything and with cosmology there rarely is an answer. Maybe somthing to do with ligt bending at the outer edge of the universe means as you get close (It expands so you can't catch up with it so metaphorically speaking) you unknowingly run round the edge a bit. Like a racing game where you run wide into the armco and are stuck on it for a few seconds.

Did that make sense?

*may have happened - don't want to upset anyone ;)
 

jez101

Bookies drive nice cars because of people like me
Contributor
Just because my parents were experts, does not mean that I am!!! Just want to make that clear:)

There is the theory of inflation (space betting exponentially bigger), which as far as I understand it is really about the stuff that we know about in space, spreading out further and further into the space that still has nothing in it (that we know about at least). If the stuff is going further and further out there, where is it going? Some people think it will turn around and come back, while others think it will keep growing at various faster / slower speeds. Fascinating stuff...
 

Brogan

🦶 Leg end
Staff Member
I sat down and tried to make sense of it all once, but decided it was beyond my comprehension.

I have no idea what is out there, or how much of it there is.
 

Speshal

World Champion
Valued Member
It's either infinitely big or infinitely small depending on which school of thought you subscribe to.
 

Mryzyz

Rookie
To be a bit more precise, the universe probably has a diameter of either 9.3 X 10^33 light years, or 9 X 10^10 light years, depending on whether it is finite but unbounded.
 

tooncheese

Hans Heyer
Contributor
To be a bit more precise, the universe probably has a diameter of either 9.3 X 10^33 light years, or 9 X 10^10 light years, depending on whether it is finite but unbounded.

I know it is 13.7 billion years old, and so can be up to 27.4 billion light years in diameter. Not sure if its american billion or british billion?:dunno:Probably American. So it is 2.74x10^10 lights years which is 1.61070895 X 10^23 miles. Also written as 161,070,895,000,000,000,000,000 miles. My brain is already worn out so I can't say how long it would take to travel across. Also Mryzyz where did you get your numbers from, I plucked mine out the sky, so yours are probably more accurate.
 
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